Home solar power system

[gizmo]

Here are a few pics of my home solar power system.

We are off-grid (not connected to mains electricity.)

This is in response to  a request from chetlaham in another thread.

I thought they might be of wider interest so I have started a new thread here.

If you have any questions I'm happy to answer them.

 

1. Photovoltaic Panels - 3 Kw of panels.

2. Hot Water panels - Rinnai/Beasley flat panel collectors.

3.Batteries - 1330 Amp-hour Exide Energystore lead-acid, 12 cells of 2 volts = 24 volt system.

4. Control panel - breakers, solar charge regulators, inverter. Tall regulator is Apollo T80, the older one. The blue one is Victron 70 amp, a recent addition.

5. Inverter - Latronics 24 volt 3000 watt (continuous) sine-wave inverter. Steps up the 24 volts DC at the batteries to 240 volts AC for the house supply.

6. display on the Apollo regulator. Shows batteries are 100% full at midday. I have power to spare - maybe I will bake something?

7. Indoor display - the equipment is in its own shed, this is the in-house display so we can monitor things without going out to the shed.

Note the solar panels are wired as a 48 volt array, the batteries are 24 volt, the regulators electronically match the solar voltage to the battery voltage, this is much more effective on cloudy days than a system where solar volts match battery volts.

8. Indoor display - today's harvest so far.

If I don't burn up some more power this afternoon, the harvest won't increase much. If I burn up some amps with some baking, washing, pump water up hill, then the power used will be replaced by solar to replenish the batteries, so the harvest will increase. Our highest harvest days are about 12 kWh.

 

[revvinkevin]

WOW Chris, that is really awesome!

I had a solar system (22 panels) installed on my home back in November and while I cannot say I am “off the grid“ (unfortunately), I am currently only paying the fee to be connected to our local power utility for times like now, when it’s dark and I’m not generating my own power. So far it looks as if I am generating at least equal to, if not slightly more power than I am actually using on a daily basis, which was my goal. I’m looking forward to see how it all works out during the summer when I’m running my A/C a lot![this post was last edited: 3/5/2021-21:57]

 

[maytag85]

Since my folks have solar, there are no more complaints about $500 electric bills in the summer anymore and it’s the same kind of solar like Kevin has where it supplements your electric bill to keep the cost of electricity low. Since I have my ‘63 Whirlpool Imperial dryer with the dual wattage element, I usually run it on the super speed during the day when the sun is out since it’s pulling power from the solar panels when the sun is out, and when it’s night I usually run it on the normal speed since it’s pulling power from the grid, just some food for thought.

 

[bradfordwhite]

Awesome installs guys!

 

 

 

[Chetlaham]

All thats missing is the mini U253 heavy water reactor.

 

 

 

(Kidding)

 

 

Thanks for the pics, I love the install!

 

 

[gizmo]

All thats missing is the mini U253 heavy water reactor.

It runs off the only safe nuclear reactor - the sun.

You asked for that...

 

[gizmo]

power to spare...

As mentioned above I had power to waste this afternoon so turned solar energy into banana muffins.

Total harvest today 5.9 kWh.

 

[Chetlaham]

Sun is good!

Do you have any DC outlets in your home? Or lighting? I like to avoid the inverter as much as possible- but thats just me.

 

[gizmo]

We have a few DC outlets and DC lights.

My initial idea, like yours, was to avoid using the inverter when possible, and for items that are powered up 24/7, to run off DC so the inverter goes in to sleep mode when nothing else is on. Also to give some available power source if the inverter fails.

 

the reality has been different. We don't use any of the DC power outlets any more. The inverter powers some 24/7 items so it hasn't gone into sleep/standby mode for years. (for example phone chargers.) We have big enough batteries and enough solar panels that this just isn't an issue.

 

The last item we used on a DC outlet was a small 12 volt fan we put behind our wood heater to increase air circulation. We have replaced that with one of those heat-powered fans that sits on top of the heater - when the base of the fan gets hot, it powers a thermo-electric module that powers a small DC fan. The older fan was a bit noisy, the new one is silent.

 

Our fridge is 240 volt, a cheap Chinese 2 door which has been very efficient. It is not frost free in the freezer, and the fridge compartment defrosts by natural warming of the back wall, which means when the thermostat clicks off, it uses zero power, which I like. We ran heavy 24 volt cables to the fridge alcove in the kitchen when the house was built, intending we would get a super-efficient DC fridge. These cables have never been used. It is cheaper to get extra solar panels and run a normal fridge than to buy an over-priced DC fridge and they are not very efficient any way. It seems DC fridge technology stagnated about 20 years ago and AC fridges have improved efficiency in leaps and bounds. If you look up any special "high efficiency" DC fridge for RV use, they consume way more than a highly efficient domestic fridge. For example, a friend asked me about getting a DC fridge, the one he was interested in boasted that it used "only" 1 kwh/day. Mine uses 1/2 a kwh/day.

We also ran DC cables to the laundry for a DC washing machine. I have converted washing machines myself in the past but current technology is so efficient that it isn't worth the bother. These DC cables too have never been used, they are still in the wall.

 

The only DC circuits we still use are two spotlights in the kitchen over the benchtops, and a light in the pantry. All other lights run from the inverter.

 

We have had 2 inverters in this house, a 1500 watt sine wave that sh*t it capacitors at about 10 years old, we had it repaired but upgraded to a 3000 watt model not long after. We were told that if we bought a bigger inverter, it would have an easier life and last longer. The bigger one also sh*t its capacitors at about 10 years old, but we have added more power-hungry gadgets since we bought it, so it probably didn't get the easier life we intended. It was repaired by the manufacturer (it is an Australian product) and we are very happy with it.

If we were building again, I would have to think hard if I bothered with DC circuits in the house. It added quite a bit of expense and has been hardly used. we had a run of about 30 metres of very heavy cables from battery shed to house; DC wiring through the house, much of which has never been used; weird power outlets that were hard to source and expensive; a DC sub-board with breakers and the 24:12 volt DCC converter on it. It doesn't really make sense, but I kind of like having it. We have neighbours (very good friends) who are also off grid solar, they have kept their old inverter when they upgraded, so if either of us have an inverter failure, we have a spare to use while ours is being fixed.

I just remembered another DC circuit still in operation. we have a tiny DC circulating pump in our hot water system. Our hot water cylinder is at the peak of the roof, above the second storey and all the water outlets are at ground floor level. (Yes, no upstairs bathroom, how do we survive??) This means long runs of pipe and low pressure gravity feed hot water, so I have fitted a circulating pump that takes water from the end of the line and returns it to the header tank. we press a button on the wall and the pump runs for 20 seconds, thus purging cold water from the hot water pipes without wasting a drop down the drain. (We catch our own rainwater, too.)

 

Photos:

1. DCC converter 24 volts to 12 volts for DC wall outlets, pump and lights.

2. DC sub-board in the loft for DC circuits in the house.

3. 12 volt DC power outlet on left, 240 volt power outlet (standard Australian power point) on right.

The 2-pin plug with one horizontal and one vertical pin is the correct standard for DC power outlet 15 amp up to 32 volts DC. (mine are 12 volts DC.)

Sorry about the poor photos, there isn't a lot of light in the storage loft.

 

[sudsmaster]

Very cool.

I was talking to a friend the other day. We were talking about his Prius. I volunteered that I would probably get an all-electric car, and charge it from a solar panel. I have some good spots to mount the panels, either on top of the carport roof, or on top of the fish pond "roof" (really a 15'x15' area that is well supported by steel posts and beams, 2x4's, and 2x2' in a slatted patter to let light and rain through. I can walk up there, no problem, so the weight of a solar array shouldn't be a concern.

The only hitch might be getting it approved by the inspector(s). Already I've been told by Tesla that a metal roof over an adjacent enclosed patio would not be approved. Because, I suppose, well, metal conducts electricity.

I really don't want solar panels on the house roof itself. Not when I have better locations.

 

[gizmo]

Steel roof on metal structure...

That's exactly what I have. Steel roof, steel frame, steel walls. What's the problem? Make sure the structure is grounded, it should be fine. Don't rely on Tesla, find out who the inspector is and talk to them direct.

Talk to some solar installers. You would want plenty of panels to run a car, both carport AND fish pond roof would be my guess, though you are in Sunny California...

 

[wayupnorth]

I would love to add solar, but with 3/4 of the year lower sun level and all the trees and SNOW, it wouldn't work well when I want it. But my front has (8) 5'x 6' windows so I do get alot of passive solar in the afternoon, as the sun always sets right in front of me, thats when it is out. We are starting to get to the higher sun angle now and that means warmer weather, thankfully.

 

[bradfordwhite]

Dont give up on solar if you live in a northern region.

The only difference between a solar system in southern California and Maine is the number of panels needed. All other components are the same.
batteried, charge controllers, and all other devices connected after the charge contoller.

In a northern region one would need about twice the number of solar panels that the only difference and those are resonably innexpensive these days.

Also, solar panels prefer cooler climate. That hot sun in California for example is not the preferred temperature for the panels or the other equipment.

You're also less likely to have zoning issues in Maine vs. California.

 

[bradfordwhite]

It's cool to see a company like Zillow listing Sun numbers on their listings.

No matter where you are you can find out how many sun hours your location gets to help in figuring your solar panel needs.

https://www.sunnumber.com/

 

[sudsmaster]

Thanks Chris/Gizmo!

I will definitely check out some non-Tesla solar installers.

One reason why I want to keep the panels off the roof is because I figure the penetrations to support the panels might shorten the life of the roofing. Another reason why I didn't want to go with Tesla for their solar roofing tiles is because of the initial expense and the complications involved with repairing the roofing later (locked into a proprietary roofing tile design). Current the house has a 40 yr old heavy shake roof. It's probably at EOL. I have extended its life by replacing shakes as needed, primarily on the south and west facing sides.

 

[easy]

Home Solar

I live in Massachusetts and have a system that sounds a little different than the others discussed here. It may not be applicable in your state, but if you're considering solar it might be wise to do some research.

In Massachusetts, we have something called net metering. The panels generate more power than I can use in the summer so the system pumps the power back into the grid.
The electric meter actually spins backwards and generates a credit on your electric bill. I still have a credit from what I generated last summer so I've been paying nothing on my electric bill.

The system was designed to generate kw based on my average use prior to the installation. If the system does not generate that amount (say due to cloudy weather), I will get a check for the difference.

Most importantly, I lease the panels from the solar company. I got free panels, free installation, and free repairs for the life of the lease. They also reinforced the roof in the attic due to the weight of the panels. The only cost was that I had to sign over the federal tax credit to the company. I pay a monthly fee to the solar company that was based on a percentage of my then monthly electric bills

I believe the leasing option is available anywhere but not net metering. The utilities hate it but Massachusetts is liberal and has voted to renew it several times.

David

 

[gizmo]

net metering

We are off grid so it doesn't apply to us, but our state (Victoria) used to have net metering for homes with the old style "moving disc" meters. All grid connected homes (with or without solar) got upgraded to smart meters a few years ago. For an initial incentive period, the power companies had to pay a mandated 60c per kwh for your exports. Retail price of electricity about 30c so a good incentive to fit solar.

That price was dropped to 45c then unregulated, export price fell to 6 to 8c per kwh, now back up to about 11 or 12c. A few lucky folks signed long term contracts at 45c, they will still get that for another couple of years.

 

[warmsecondrinse]

You mentioned you used the extra power production to bake (banana?) bread. Your oven and/or hob are electric? Doesn't that suck a lot of juice from the batteries if you cook at night or on a cloudy day? Or is that not a factor?

Thanks,

Jim

 

[gizmo]

electric oven

One of the keys to living well off-grid in a place with variable weather  is to have options.

Our main stove is gas (LPG) but I have an array of benchtop gadgets that get used most of the year and have a break over winter.

I have a Russell Hobbs benchtop oven. It sits in the pantry till it comes out to play. Link below.

I place two pine cutting boards on top of my gas stove and place the oven there. (The boards are cut to fit the stove perfectly, and stand upright in my pot drawers when not in use.) This keeps the oven under the rangehood.

I do the same for induction hotplate, rice cooker, toaster, bread maker and Tefal cook-4-me+ multi-cooker.

I only have single induction hotplate, I use a rice cooker as an extra saucepan if I need to. (I have two Breville rice cookers.)

the rice cookers only use 500w so they are great. The induction hotplate goes up to 2000w but I tend to use it under 1000w - maybe 1000 or 1200 to bring something up to temp, then drop back to 400w to continue cooking. Its display shows Watts so that is easy to monitor.

https://www.cheapaschips.com.au/products/ka7931

 

When the sun doesn't shine, we use gas.

We can still use the electric cooking gadgets in the evening after sun goes down, but if the forecast is for bad weather I tend to cook on gas. Tomorrow's weather is more important than today's in terms of replenishing batteries after cooking at night.

 

When I posted above, it was a reasonably sunny day, we had power to burn. we don't need clear blue sky, bright overcast works fine and we get lots of that here, it is sort of our default weather. Yesterday was foggy all day so we cooked on gas.

Russell Hobbs - Compact Kitchen Convection Oven with Hotplates | Russell Hobbs Australia

The Compact Kitchen Toaster Oven with Hotplates from Russell Hobbs is the handy, space saving appliance you’ve been waiting for! This compact, convenient and versatile Toaster Oven with Hotplates is ideal for roasting, baking, boiling, frying and grilling to perfection.

au.russellhobbs.com